Purine compounds and methods of preparing the same



PURINE COMPOUNDS AND METHODS OF PREPARING THE SAME Bernard R. Baker, Nanuet, N. Y., and Robert E. Schaub, Paramus, N. J., assignors to American Cyanamid Company, New York, N. Y., a corporation of Maine No Drawing. Application October 29, 1952,

Serial No. 317,583 18 Claims. (Cl. 260-252) This invention relates to a new class of substituted purine compounds and more particularly to 2substitutedmercapto-6-disubstituted-amino-8-mercaptopurines, salts thereof, and methods of preparing the same.

e new purines of this invention can be represented by the following structural formula:

wherein R1S represents a substituted mercapto group, or in other words, R1 represents a monovalent organic substituted on the mercapto sulfur, the linkage being by carbon to sulfur bond; and

R1 represents a disubstituted amino group, or in other words, R2 and R3 represent substituents on the amine nitrogen, the linkage, in each instance, being by carbon to nitrogen bond. Suitable substituents which may be the above formula may be illustrated substituted benzyl Compounds of the above formula are of particular interest where R2 and R3 represent members selected from the group including alkyl substituents, aralkyl substituents, mono-cyclic aryl sub- Rr may represent a nitrogen containing heterocyclic ring, or instance a piperidino or morpholino radical. Compounds which at present show the greatest utility are those wherein each of the represent saturated hydrocar than about ten carbon atoms.

There is evidence to indicate that the new purines of this invention are tautomeric substances and may some times exist in a dynamic isomeric state. Such atutomerism can be illustrated by the following equation:

wherein R1, R2 and R3 are as previously defined. be understood by those skilled in th meric state can not be illustrated by It will e art that a tautovalue in the isolation and purification pounds of this invention. As previously stated, the new purine compounds also form salts with bases to give metal derivatives, for example alkaline earth metal, alkali metal and heavy metal derivatives. These metal salts of the new purine compounds, are of value in the field of synthetic chemistry. It is, therefore, intended that both the metal salts and the acid addition salts constitute a part of the present invention.

The new compounds of this invention are useful as intermediates in organic syntheses. For example, the S-mercapto group can be alkylated and a salt of the resulting di(substituted mercapto) compound reacted with an alkyl halide to give purine compounds having a substituent in the 7 or 9 position. If desired, the mercapto groups can then be removed by reduction. Alternatively, the new compounds of this invention can be employed in the production of purines by the method disclosed in U. S. application S. N. 314,406 filed October 29, 1952, which method comprises treating the mercapto purine compounds with a low temperature-Raney nickel catalyst. Other uses for the new compound of this invention will be apparent to those skilled in the art.

While it is not intended that this invention be limited to purine compounds of the above-described class when substantially complete in from about one to twenty-four hours, and at C. the reaction is substantially complete in from about one-half to one hour.

The invention will be more particularly illustrated by the following specific examples:

Example I A mixture of 12 gm. of Z-methylmercapto-4-amino-6- chloropyrimidine (Am. Chem. J., 34, 182 (1905)) and 30 cc. of 25% aqueous dimethylamine was heated in a steel bomb at C. for four hours. The solid was collected on a filter from the cooled contents and washed h water to yield about 11.8 gm. (94%) of 2-methylmercapto-4-an1ino-6-dimethylaminopyrimidine having a melting point of about 156 C.-I60 C.

To a solution of 25 gm. of 2-methylmercapto-4- with water, then heptane. Recrystallization from hepamino-fi-dimethylaminopyrimidine in 490 cc. of 10% tane gave white needles having a melting point of about acetic acid cooled to 5 C. was added portionwise with 103 C.104 C. shaking a solution of 11.6 gm. of sodium nitrite in 23 cc. A mixture of 5.8 gm. of 2-benzylmercapto-4-amino-6- of water. After two hours at C. the mixture was chloropyrimidine, 15.5 gm. of ethylene glycol monofiltered and the blue-green 2-methylmercapto-4-aminomethyl ether and 6 cc. of piperidine was refluxed for four 5-nitroso-6-dimethylaminopyrimidine was washed with hours, then evaporated to dryness in vacuo. The residue water. was shaken with 100 cc. each of water and chloroform.

To a stirred suspension of the preceding wet nitroso The separated, dried organic layer, was evaporated tocompound in 580 cc. of water heated to 50 C. was dryness in vacuo l eavi g out 5.7 gniof added 58 gm. of sodium hydrosulfite in portions over a Zylmercapt0-4-am1no-6-p1perid1nopyr1m1d1ne as an oil.

period of five to ten minutes. Ten minutes later an ad- This compound was insoluble in water, but soluble in ditional 20 gm. of sodium hydrosulfite was added. The alcohol, chloroform or ethyl acetate- The oil g v a temperature was raised to 70 C. for ten minutes. The 76% yield of picrate which formed yellow crystals having cooled mixture was filtered and the solid washed with a melting P int f a ut 194 C.195 C. from 50% alcowater. Recrystallization of a sample from alcohol gave hol. Z-methyl-mercapto 4,5 diamino-6-dimethylaminopyy p 'p p py was rimidine as white crystals having a melting point of about Converted to y p h 'p p 154 C.155 C. pyrimidine, a yellow oil, as in Example I. A solution of A solution of 1.00 gm, of Z-methylmeroaptoAj-di- 1.0 gm. of this Oil in 10 CC. of pyridine and 2 C6. of caramino-6-dimethylaminopyrimidine in 10 cc. of pyridine bon disulfide was refluxed for one-half hour, then evapand 2 cc. of carbon disulfide was refluxed on the stearnorated to dryness in vacuo. Trituration with alcohol gave bath for thirty minutes during which time hydrogen sulabout 0.46 gm. of 2-benzylmercapto-6-piperidino-8-rnerfide was evolved and the product crystallized, Th captopurine. Recrystallization afforded cream colored cooled mixture was filtered and the solid washed with 2 C y having? melting Point of about alcohol to yield about 1.12 gm. (93%) of 2-methylwith decomposition.

mercapto-6-dimethylamino-S-mercaptopurine as cream E l 1V colored crystals. This material can be obtained as white crystals by recrystallization from ethylene glycol mono- A mixture f 10 gm. of 2-methylmcrcapto-4-amino-6- methyl ether. This compound is insoluble in common chloropyrimidino and of yl ilin 8 solvents cold, but is soluble in excess aqueous or alcoholic heat d in a bath at 125 C. for twenty-two hours during alkali. which time crystals separated. Trituration of the cooled mixture with acetone gave about 14.1 gm. (87%) of 2- Example H rnethylmercapto 4-amino-6-methylanilinopyrimidine hydrochloride. Recrystallization from 25% alcohol aff 5 9 9 of y R E' forded White crystals having a melting point of about me an dlethylamme 11 253 c.-2s4 c This salt is soluble in hot alcohol but of ethylene glycol monomethyl ether was refluxed for insoluble in Watr acetone or benzene tweinty hours .then evaporated to dryness m Th6 When an alcoholic solution of the hydrochloride salt residue was dissolved in acetone, filtered from diethyla- 40 was poured into foul. volumes of dilute base 2 methy1 mine hydrochloride and the filtrate evaporated to dryness mcrcapto 4 amino 6 methy1ani1in0pyrimidine base vacuo [OJ/161d about 0. of h f arated as white crystals having a melting point of about capto'q'ammo'dlethylammopyqmldme as an 123 C-125 C This compound is insoluble in water a of of the 011 m 10 P acetic but soluble in chloroform or warm alcohol. acid was added 70 cc. of saturated p1cric acid. The 2 methy1mercapto 4 amino 6 methylanflinopyrimi picrate was collected and washed with water to yield me was nitrosated and reduced to 2-methylmercaptoabimt g of E} mammal im 4,5-diamino-6-methylanilinopyrimidine as described in P o out 8 0490 Recrystaihlatlon 9 Example I. A solution of 1.0 gm. of this triamine in 10 gati g? gg gfi g g gl having a meltmg cc. of pyridine and 2 cc. of carbon disulfide was refluxed 2 methylmercapto-4-amino-6-diethylaminopurine was gi g i g ig g igggg i gg ifii fii g g P g .reducefl 9 m ethanol gave about 0.70 gm. of 2-methylmercapto-6- a A g g? i i methylan ilino-8-mercaptopurine. Recrystallization from P s 0 mamme of ethylene glycol monomethyl ether afforded white crystals pyridine and 7.4 cc. of carbon disulfide was refluxed on W having a melting Point of about (3403a c with the steam-bath for ninety minutes, then evaporated to composition dryness in vacuo. Trituration of the residue with chlorotorm gzve about 0.77 gmilol' Z-methylmercapto-6-diethyl- Example V amino- -mercaptopurine aving a melting point of about A mixture of 10 a a gm. of 2 methylmercapto 4-am1no-6- 254 C.-257 C. Recrystallization from ethanol gave chloropyrimidine and 233 of mbuwlbenwlamim 22 rystals having a melting point of about was heated at 125 C. for six hours. The partially solid 3 a residue was partitioned between ethyl acetate and water. Example I The organic layer was washed several times with 1 N hydrochloric acid, then evaporated to dryness in vacuo. To a solution of 10 gm. of 2-mercapto-4-hydroxy-6-p 5 Crystallization of the residue from ethyl acetate-hep'tane rimidol (Ann., 331, 71) in 100 cc. of alcohol and 20 cc. g about e 0f y t of water containing 2.6 gm. of sodium hydroxide was amibo y y py Recrystallizaadded 8.1 cc. of benzyl chloride. The mixture was re- U011 from chloroform-116mm gave White Crystals having fluxed for fifteen minutes, then cooled. The white crysa melting point of about tals of Z-benzylmercapto-4-amino-6-pyrimidol were col- 2 mothylmol'capto 4 amino-o'n-butylbenlylamino' lected and washed with alcohol. Recrystallization from pyrimidine hydrochloride Was nitfosatod and reduced to a mixture of water and ethylene glycol monomethyl ether 2 mothylmefcaplo 4,5 dlamino-6I1'butYlbenZY1aminogave white crystals having a melting point of about 243 pyrimidine 35 described in Example A Solution of C.-243.5 C. gm. of this triamine in 11 cc. of pyridine and 2 cc. of car- A mixture of 11.3 gm, of 2-bcl]Zylmercapto-4-;m in -6- bon disulfide was allowed to stand for twenty-four hours. hydroxypyrimidine, 3 cc. of dimethylaniline and 57 cc. of Part of the solvont'was removed n vacuo and the S0111- phosphorus oxychloride was refluxed for eight hours, tioll was P into Several Volumes of about 05 N then concentrated to a syrup in vacuo and poured into Sodlum hydfoxido- Solution was Clarified y filtra- 200 cc. of water. The mixture was warmed on the steam tion thfollgh come, then Nofit- The filtrate s a i ibath, then made strongly ba i ith excess 23% 30 fied with acetic acid and the crude solid collected. Remonia water and heated on the steam-bath for one hour. orysiallilation from chlol'ofofmhepmno g White y The mixture was cooled. The solid was collected and i818 of z-mothylmol'oapto'b-mblltylbenzylamino-B-moF- washed with water, then triburated with 25 cc. of 1 N captopurine having a melting point of about sodium hydroxide. The cyrstals of 2-benzylmercapto-4- 201 C amino-6-chloropyrimidine were collected and washed 35 Other 2-substituted-mercapto6-disubstituted-amino-8- mercaptopurines are prepared by the same procedures as illustrated in the above examples.

We claim:

1. The new compound 2-benzylmercapto-6-piperidino- 8-mercaptopurine.

he 2 lower-alkylmercapto-6-di-lower-alkylamino- 8-mercaptopurines.

he new compound Z-methylmercapto-6-di-loweralkylamino-S-mercaptopurine.

4. The new compound 2-methylmercapto-6-diethylamino-8-mercaptopurine.

The 2 lower alkylmercapto 6-lower-alkyl-lowermononuclear-aralkylamino-8-mercaptopurines.

e new compound Z-methylmercapto-6-n-butylbenzylamino-8-mercaptopurine.

7. The 2 lower alkylmercapto 6-lower-alkyl-lowermononuclear-arylamino-8-mercaptopurines.

8. The new compound 2-methylmercapto-G-methylanilino-S-mercaptopurine.

9. The method which comprises contacting with carbon disulfide a 2-lower-alkylmercapto-4,5-diamino-6-di-loweralkylaminopyrimidine, said contact being effected in a pyridine solvent at a temperature of from about 25 C.- 100 C.

10. The method of claim 9 when said 2-lower-alkylmercapto-4,5-diamino-6-di-lower-alkylaminopyrimidine is 2 methylmercapto 4,5-diamino-6-dimethylaminopyrimidine.

11. The method of claim 9 when said 2-lower-alky1- mercapto-4,5-diamino-6-di-lower-alkylaminopyrimidine is Z-methylmercaptol,S-diamino-6-diethylaminopurine.

12. The method which comprises contacting with carbon disulfide a 2-loweralkylmercapto-4,5-diamino-6- lower alkyl-lower-mononuclear-aralkylaminopyrimidine, said contact being effected in a pyridine solvent at a temperature of from about 25 C-100 C.

13. The method of claim 12 when said 2-lower-alkylmercapto 4,5-diamino-6-lower-alkyl-lower-mononucleararalkylaminopyrimidine is 2-methylmercapto-4,S-diaminofi-n-butylbenzylaminopyrimidine.

14. The method which comprises contacting with carbon disulfide a 2 lower alkylrnercapto-4,5-diamino-6- lower-alkyl-lower-mononuclear-arylaminopyrimidine, said contact being effected in a pyridine solvent at a temperature of from about 25 C.-100 C.

15. The method of claim 14 when said 2-lower-alkylmercapto-4,S-diamino-6-lower-alkyl-lower mononucleararylaminopyrimidine is Z-methylmercapto-4,5-diamino-6- methylanilinopyrimidine.

16. The method which comprises contacting with carbon disulfide 2-benzylmercapto-4,5-diamino-6-piperidinopyrimidine, said contact being effected in a pyridine solvent at a temperature of from 25-100 C.

17. Compounds having the general formula:

wherein R1 is a member selected from the group consisltmg (21f lower-alkyl and 1ower-mononuclear-aralkyl radica s an is a member of the group consisting of di-lower-alkylamino, di-mononuclear-arylamino, mononuclear-aryllower alkylamino, di-lower-mononuclear-aralkylamino, mononuclear aryl -lowermononucleararalkylamino, lower-a1kyl-lower-mononuclear-aralkylamino and piperidino radicals.

18. A method for preparing compounds having the general formula wherein R1 is a member selected from the group consisting of lower-alkyl and lower-mononuclear-aralkyl radicals and R1SC/ \CN n l Ra --NH: 11TH: said contact being effected in an inert solvent.

No references cited. 

17. COMPOUNDS HAVING THE GENERAL FORMULA:
 18. A METHOD FOR PREPARING COMPOUNDS HAVING THE GENERAL FORMULA 